It's still being updated. I don't see anything on the virt-manager homepage or GitHub that would suggest it is deprecated.

https://virt-manager.org/

https://github.com/virt-manager/virt-manager

It can't do literally everything Qemu/libvirt can do using only the UI, but given that it has escape hatches to directly edit libvirt configurations, and libvirt has escape hatches to directly pass arguments to Qemu, there's very little you can't do with it.